In the US, I always put a little water in the pan on low heat and steamed them until the water was almost gone. I'd remove it from the heat, then drain the water, add a fat, and then fry until the skins turned. I will admit that either my mother in law pans are wonky or the casings on sausages are different here, but I've not been able to use that method here without the skins splitting or the sausages sticking. I use the slow heat method mentioned above, but I add a fat to the pan. I might try it without it the next time we have sausages.